Medical catheterizations are routinely carried for many procedures. In one representative example, cardiac arrhythmias including atrial fibrillation may be diagnosed as well as treated by employing a variety of catheters to access the patient's heart in a minimally invasive manner. Diagnosing such conditions may involve mapping the cardiac tissue to locate aberrant electrical pathways and currents within the heart, as well as to determine mechanical and other aspects of cardiac activity. Various methods and devices have been described for mapping the heart. Such methods and devices are described, for example, in U.S. Pat. Nos. 5,471,982, 5,391,199 and 5,718,241 and in PCT patent publications WO94/06349, WO96/05768 and WO97/24981. Further, one or more catheters may also be employed to deliver energy to desired locations within the patient's anatomy to pace the heart or to ablate tissue and form nonconductive lesions that may block or modify the propagation of unwanted electrical signals from their origin to help restore more normal function. As will be appreciated, these examples are for the purposes of illustration only, as a wide variety of other procedures may be facilitated through use of suitable catheterization techniques. Typically, the ability to control the exact position and orientation of the catheter tip is critical and largely determines how useful the catheter is.
To that end, directional catheters have been designed to be deflectable, such as by manipulation of a puller wire or other deflection member disposed within an off-axis lumen and attached to a distal location of the catheter. Correspondingly, applying tension to the puller wire causes the tip of the catheter to deflect. Various designs exist, including uni-directional catheters that employ a single puller wire and bi-directional catheters that may have two puller wires extending within opposing off-axis lumens. More complex designs featuring a greater number of puller wires are also possible. Such catheters typically have a control handle at their distal end which have a thumb knob, a rotatable grip or other actuation mechanism that is manipulated by an electrophysiologist to position a distal end of the catheter at the desired location and/or operate electrode assemblies, such as contraction, expansion, deployment, retraction, etc.
As with all medical equipment, prevention of iatrogenic conditions is of paramount concern. Ensuring sterility of the catheter may help minimize the risk of transmitting infectious agents. One strategy involves using new equipment with each procedure. With more complex equipment, such as the catheters of this disclosure, this may represent a significant cost. To address this concern, the equipment may be cleaned and sterilized before the next use. However, costs and delays are associated with this strategy as well, particularly due to the difficulties involved with cleaning the elongated catheter shaft which typically has multiple lumens. Accordingly, it would be desirable to provide a catheter system that reduces these drawbacks by employing a reusable handle mechanism that may be readily sterilized for use with a disposable catheter body, particularly in light of the observation that the handle represent a significant fraction of the overall cost. Similarly, it would be desirable to provide a catheter system having a detachable connection between the reusable handle and the disposable shaft that couples the actuation mechanisms of the handle with components of the catheter shaft, such as puller wires, that control deflection of the catheter tip. The techniques of this disclosure as described in the following materials satisfy these and other needs.